Toxic potentiality of bio-oils, from biomass pyrolysis, in cultured cells and Caenorhabditis elegans.

Bio-oils, which are multicomponent mixtures, were produced from two different biomass (rice straw (rice oil) and sawdust of oak tree (oak oil)) by using the slow pyrolysis process, and chemical compositional screening with GC-MS detected several hazardous compounds in both bio-oil samples. The two bio-oils vary in their chemical compositional nature and concentrations. To know the actual hazard potentialities of these bio-oils, toxicological assessments were carried out in a comparative approach by using in vitro (Jurkat T and HepG2 cell) as well as in vivo (Caenorhabditis elegans) systems. A dose-dependent increase in cytotoxicity, cell death (apoptosis), and genotoxicity were observed in cultured cell systems. Similarly, the in vivo system, C. elegans also displayed a dose-dependent decrease in survival. It was found that in comparison with rice oil, oak oil displayed higher toxicity to all models systems, and the susceptibility order of the model systems were Jurkat T > HepG2 > C. elegans. Pursuing the study further toward the underlying mechanism by exploiting the C. elegans mutants screening assay, the bio-oils seem to mediate toxicity through oxidative stress and impairment of immunity. Taken together, bio-oils compositions mainly depend on the feedstock used and the pyrolysis conditions which in turn modulate their toxic potentiality.

Co-production of furfural and acetic acid from corncob using ZnCl2 through fast pyrolysis in a fluidized bed reactor.

Corncob was pyrolyzed using ZnCl2 in a pyrolysis plant equipped with a fluidized bed reactor to co-produce furfural and acetic acid. The effects of reaction conditions, the ZnCl2 content and contacting method of ZnCl2 with corncob on the yields of furfural and acetic acid were investigated. The pyrolysis was performed within the temperature range between 310 and 410°C, and the bio-oil yield were 30-60 wt% of the product. The furfural yield increased up to 8.2 wt%. The acetic acid yield was maximized with a value of 13.1 wt%. A lower feed rate in the presence of ZnCl2 was advantageous for the production of acetic acid. The fast pyrolysis of a smaller corncob sample mechanically mixed with 20 wt% of ZnCl2 gave rise to a distinct increase in furfural. A high selectivity for furfural and acetic acid in bio-oil would make the pyrolysis of corncob with ZnCl2 very economically attractive.

Characteristics of products from fast pyrolysis of fractions of waste square timber and ordinary plywood using a fluidized bed reactor.

Fractions of waste square timber and waste ordinary plywood were pyrolyzed in a pyrolysis plant equipped with a fluidized bed reactor and a dual char separation system. The maximum bio-oil yield of about 65 wt.% was obtained at reaction temperatures of 450-500 °C for both feed materials. For quantitative analysis of bio-oil, the relative response factor (RRF) of each component was calculated using an effective carbon number (ECN) that was multiplied by the peak area of each component detected by a GC-FID. The predominant compounds in the bio-oils were methyl acetate, acids, hydroxyacetone, furfural, non-aromatic ketones, levoglucosan and phenolic compounds. The WOP-derived bio-oil showed it to have relatively high nitrogen content. Increasing the reaction temperature was shown to have little effect on nitrogen removal. The ash and solid contents of both bio-oils were below 0.1 wt.% due to the excellent performance of the char separation system.

Fast pyrolysis of palm kernel shells: influence of operation parameters on the bio-oil yield and the yield of phenol and phenolic compounds.

Palm kernel shells were pyrolyzed in a pyrolysis plant equipped with a fluidized-bed reactor and a char-separation system. The influence of reaction temperature, feed size and feed rate on the product spectrum was also investigated. In addition, the effect of reaction temperature on the yields of phenol and phenolic compounds in the bio-oil was examined. The maximum bio-oil yield was 48.7 wt.% of the product at 490 degrees C. The maximum yield of phenol plus phenolic compounds amounted to about 70 area percentage at 475 degrees C. The yield of pyrolytic lignin after its isolation from the bio-oil was approximately 46 wt.% based on the water and ash free oil. The pyrolytic lignin was mainly composed of phenol, phenolic compounds and oligomers of coniferyl, sinapyl and p-coumaryl alcohols. From the result of a GPC analysis, the number average molecular weight and the weight average molecular weight were 325 and 463 g/mol, respectively.